For vim/evil, the following works.

    ASCII Name          - Vim Insert    - Visual Repr
    --------------------------------------------------    
    Start of Heading    - Ctrl-v Ctrl-a - ^A
    Start of Text       - Ctrl-v Ctrl-b - ^B
    End of Text         - Ctrl-v Ctrl-c - ^C
    End of Transmission - Ctrl-v Ctrl-d - ^D
    File Separator      - Ctrl-v Ctrl-\ - ^\
    Group Separator     - Ctrl-v Ctrl-] - ^]

For insertion you can also always just Ctrl-v DDD or Ctrl-v xHH where DDD is the three digit decimal value or HH is two hex values of the ascii code.